so the add to cart button works on the category view page but not working on the product detail page... its a clean magento 184.108.40.206 install with the the ultimo theme 1.15.2 with their demo package installed. everything is fine except this add to cart button problem.
any hep will be welccome
So, it seems it was an error by the developer as he had gone made some changes in the /addtocart.phtml file
copied the original theme file back and it fixed it.
thanks for the help anyway...